Obtention of biochar-Fe/Ce using Punica granatum with high adsorption of ampicillin capacity.

This research presents the obtaining of a biochar (CB) from the use of pomegranate peel (Punica granatum) conditioned with iron and cerium nanoparticles (C-Fe/Ce), as well as its characterization by SEM (Scanning Electronic Microscopy), FTIR (Fourier Transform Infrared Spectrometry), TGA (Thermogravimetric analysis), EDS (Energy Dispersive Spectroscopy), XPS (X-Ray Photoelectron Spectroscopy) and evaluation of the adsorption capacity of ampicillin (AMP) in aqueous phase at 20, 30 and 40 °C. The maximum adsorption capacity for CB was 18.97 mg g-1 and for C-Fe/Ce, 27.61 mg g-1 at pH of 7, observing that with increasing temperature, the sorption capacity decreases in both materials, the experimental data was fitted to various mathematical models and the best fit was the pseudo-second order model for the kinetics, whilst for the adsorption isotherms the best fit was with the Langmuir model, indicating that the adsorption process is carried out in a monolayer on a homogeneous surface, through a chemisorption process. According to the thermodynamic parameters this process is carried out through an exothermic reaction. The results obtained indicate that both materials are suitable for the removal of AMP in the aqueous phase and that they can be reused up to 5 times.

Obtention of biochar-Ca nanoparticles using Citrus tangerina׃ A morphological, surface and study remotion of Aflatoxin AFB1.

This work presents the formation of biochar with calcium nanoparticles (NPsCa) in function of pyrolysis time (C10, C30, C60, C120 and C180 min) using the Citrus tangerina peel and their evaluation in the remotion of Aflatoxin B1 (AFB1) in aqueous phase. Firstly, the Citrus tangerina was studied by Thermogravimetric analysis to determine the optimal temperature (TGA), obtaining a result of 600 °C. The biochar (NPsCa) were characterized by Scanning Electronic Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), as well as surface properties including the identification of functional groups by Fourier Transform Infrared Spectrometry (FTIR), and energetic states through the X-Ray Photoelectron Spectroscopy (XPS). The adsorption studies were carried out on the different materials and later, the experimental data was adjusted to different mathematical models, obtaining the best fit of the kinetic data to the Ho-McKay model, whilst the adsorption isotherms were adjusted to the model of Langmuir, which indicates that the Aflatoxin B1 adsorption process is carried out through a monolayer chemisorption process with maximum sorption capacities (qm) ranging between 15.72 and 63.22 µg g-1 with the 180th minute being the adequate time to obtain the carbon with the best surface properties and the best adsorption capacity. Additionally, it was observed that each material can be reused up to five times in accordance with the results from the reuse cycles.

Context-specific functions of Notch in Drosophila blood cell progenitors.

Drosophila Larval hematopoiesis takes place at the lymph gland, where myeloid-like progenitors differentiate into Plasmatocytes and Crystal Cells, under regulation of conserved signaling pathways. It has been established that the Notch pathway plays a specific role in Crystal Cell differentiation and maintenance. In mammalian hematopoiesis, the Notch pathway has been proposed to fulfill broader functions, including Hematopoietic Stem Cell maintenance and cell fate decision in progenitors. In this work we describe different roles that Notch plays in the lymph gland. We show that Notch, activated by its ligand Serrate, expressed at the Posterior Signaling Center, is required to restrain Core Progenitor differentiation. We define a novel population of blood cell progenitors that we name Distal Progenitors, where Notch, activated by Serrate expressed in Lineage Specifying Cells at the Medullary Zone/Cortical Zone boundary, regulates a binary decision between Plasmatocyte and Crystal Cell fates. Thus, Notch plays context-specific functions in different blood cell progenitor populations of the Drosophila lymph gland.

A genetic toolkit for the analysis of metabolic changes in Drosophila provides new insights into metabolic responses to stress and malignant transformation.

Regulation of the energetic metabolism occurs fundamentally at the cellular level, so analytical strategies must aim to attain single cell resolution to fully embrace its inherent complexity. We have developed methods to utilize a toolset of metabolic FRET sensors for assessing lactate, pyruvate and 2-oxoglutarate levels of Drosophila tissues in vivo by imaging techniques. We show here how the energetic metabolism is altered by hypoxia: While some larval tissues respond to low oxygen levels by executing a metabolic switch towards lactic fermentation, the fat body and salivary glands do not alter their energetic metabolism. Analysis of tumor metabolism revealed that depending on the genetic background, some tumors undergo a lactogenic switch typical of the Warburg effect, while other tumors do not. This toolset allows for developmental and physiologic studies in genetically manipulated Drosophila individuals in vivo.

Hydroxylation and translational adaptation to stress: some answers lie beyond the STOP codon.

Regulation of protein synthesis contributes to maintenance of homeostasis and adaptation to environmental changes. mRNA translation is controlled at various levels including initiation, elongation and termination, through post-transcriptional/translational modifications of components of the protein synthesis machinery. Recently, protein and RNA hydroxylation have emerged as important enzymatic modifications of tRNAs, elongation and termination factors, as well as ribosomal proteins. These modifications enable a correct STOP codon recognition, ensuring translational fidelity. Recent studies are starting to show that STOP codon read-through is related to the ability of the cell to cope with different types of stress, such as oxidative and chemical insults, while correlations between defects in hydroxylation of protein synthesis components and STOP codon read-through are beginning to emerge. In this review we will discuss our current knowledge of protein synthesis regulation through hydroxylation of components of the translation machinery, with special focus on STOP codon recognition. We speculate on the possibility that programmed STOP codon read-through, modulated by hydroxylation of components of the protein synthesis machinery, is part of a concerted cellular response to stress.

The natural flavonoid silybin improves the response to Photodynamic Therapy of bladder cancer cells.

Photodynamic Therapy (PDT) is an anticancer treatment based on photosensitisation of malignant cells. The precursor of the photosensitiser Protoporphyrin IX, 5-aminolevulinic acid (ALA), has been used for PDT of bladder cancer. Silybin is a flavonoid extracted from Silybum marianum, and it has been reported to increase the efficacy of several anticancer treatments. In the present work, we evaluated the cytotoxicity of the combination of ALA-PDT and silybin in the T24 and MB49 bladder cancer cell lines. MB49 cells were more sensitive to PDT damage, which was correlated with a higher Protoporphyrin IX production from ALA. Employing lethal light doses 50% (LD50) and 75% (LD75) and additional silybin treatment, there was a further increase of toxicity driven by PDT in both cell lines. Using the Chou-Talalay model for drug combination derived from the mass-action law principle, it was possible to identify the effect of the combination as synergic when using LD75, whilst the use of LD50 led to an additive effect on MB49 cells. On the other hand, the drug combination turned out to be nearly additive on T24 cells. Apoptotic cell death is involved both in silybin and PDT cytotoxicity in the MB49 line but there is no apparent correlation with the additive or synergic effect observed on cell viability. On the other hand, we found an enhancement of the PDT-driven impairment of cell migration on both cell lines as a consequence of silybin treatment. Overall, our results suggest that the combination of silybin and ALA-PDT would increase PDT outcome, leading to additive or synergistic effects and possibly impairing the occurrence of metastases.

Photodynamic inactivation of Gram-positive bacteria employing natural resources.

The aim of this paper was to investigate a collection of plant extracts from Argentina as a source of new natural photosensitizers (PS) to be used in Photodynamic Inactivation (PDI) of bacteria. A collection of plants were screened for phototoxicity upon the Gram-positive species Staphylococcus epidermidis. Three extracts turned out to be photoactive: Solanum verbascifolium flower, Tecoma stans flower and Cissus verticillata root. Upon exposure to a light dose of 55J/cm(2), they induced 4, 2 and 3logs decrease in bacterial survival, respectively. Photochemical characterisation of S. verbascifolium extract was carried out. PDI reaction was dependent mainly on singlet oxygen and to a lesser extent, on hydroxyl radicals, through type II and I reactions. Photodegradation experiments revealed that the active principle of the extract was not particularly photolabile. It is noticeable that S. verbascifolium -PDI was more efficient under sunlight as compared to artificial light (total eradication vs. 4 logs decrease upon 120min of sunlight). The balance between oxidant and antioxidant compounds is likely to be masking or unmasking potential PS of plant extracts, but employing the crude extract, the level of photoactivity of S. verbascifolium is similar to some artificial PS upon exposure to sunlight, demonstrating that natural resources can be employed in PDI of bacteria.

Changes in actin and E-cadherin expression induced by 5-aminolevulinic acid photodynamic therapy in normal and Ras-transfected human mammary cell lines.

Photodynamic therapy (PDT) is an anticancer treatment based on light-induced destruction of photosensitised malignant cells. It has been reported that PDT strongly affects cell-cell and cell-substrate adhesion through the reorganization of some cytoskeletal and adhesion proteins. The aim of the present work was to study the changes induced by PDT employing aminolevulinic acid (ALA), on the cytoskeleton actin network and E-cadherin expression. We employed the normal mammary HB4a cell line and its tumor counterpart transfected with the oncogene H-Ras, which has been shown to be resistant to PDT. Ras insertion induces per se disorganization of both F-actin and E-cadherin distribution. ALA-PDT induces on HB4a cells a dramatic disorganization of actin stress fibers, resembling normal Ras-transfected cells. After 48h some features of disorganization remain present. In HB4a-Ras cells, F-actin exhibits signals of photodamage, but distribution is recovered 24h after treatment. On the other hand, PDT did not impact on E-cadherin distribution, other than a transient disorganization, which was recovered at 24h. Moreover, E-cadherin disorganization did not favoured cell-cell detachment after PDT of HB4a-Ras cells. Actin but not E-cadherin constitutes in this model an important target of PDT. The fact that some features of microfilament disorganization remain present in HB4a surviving cells but not in Ras-transfected cells, suggests that cytoskeletal structures such as F-actin may be involved in the mechanisms of resistance to PDT.

Cytotoxic effects of Argentinean plant extracts on tumour and normal cell lines.

In the search for possible new anti-cancer agents, we investigated the effects of 75 aqueous and methanol extracts from 41 Argentinean plant species. The effect in cell growth was evaluated in the LM2 mammary adenocarcinoma cells. In a second stage, the highly active selected extracts were assayed in 3 other tumour cell lines: melanoma B16, bladder MB49 and lung A549; and 3 normal cell lines: mammary Hb4a and keratinocytes PAM212 and HaCat. Eight methanol extracts were found to be highly cytotoxic: Collaea argentina leaf, Iochroma australe leaf, Ipomoea bonariensis flower, Jacaranda mimosifolia flower, Solanum amygdalifolium flower, Solanum chacoense leaf, Solanum sisymbriifolium flower and Solanum verbascifolium flower. However, extract inhibition on cell growth was highly dependent on cell type. In general, except for the highly resistant cell lines, the inhibitory concentrations 50% were in the range of 10-150 µg/ml The eight extracts highly inhibited cell growth in a concentration-dependent manner, and in general the methanol extracts were always more active than the aqueous. Murine cells appear to be more sensitive than human cells to the cytotoxic action of the plant extracts. The human melanoma B16 line was the most resistant to four of the extracts. In terms of selectivity, S. verbascifolium was the species which showed most selectivity for tumour cells. Overall, this is one of the first studies focusing on southern South American native plants and their biological effects. Since some species of 5 genera analyzed have been reported to possess different degrees of alkaloid content, we examined microtubule structures after extract treatments. The eight extracts induced destabilization, condensation and aggregation of microtubules in LM2 cells, although no depolarization, typical of Vinca alkaloids damage was observed. In a near future, antitumour activity of purified fractions of the extracts administered at non-toxic doses will be assayed in transplantable murine tumour models.

Transmission of Streptococcus pyogenes causing successive infections in a family.

The objective of this study was to determine the characteristics of Streptococcus pyogenes isolated during a 10-month period from members of a family with infections and asymptomatic carriage. T-serotyping and pulsed-field gel electrophoresis confirmed that distinct GAS clones were introduced into the family over a short period of time.